cpuidle: remove unused 'governor_data' field

As far as I can see, this field is never used in the code.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Len Brown <len.brown@intel.com>

include/linux/cpuidle.h

@@ -98,7 +98,6 @@ struct cpuidle_device {
 	struct list_head 	device_list;
 	struct kobject		kobj;
 	struct completion	kobj_unregister;
-	void			*governor_data;
 };
 
 DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);